Titanium alloys can provide low-weight corrosion-resistant structures and therefore have been used in a variety of applications. For example, Ti-6Al-4V, in weight percent, is a commercial alloy widely used for aerospace and medical applications. There are other applications which could also benefit from the use of titanium alloys, in various industry sectors such as defense, energy, chemical processing, marine, and transportation. However, the material and processing costs of the titanium can be prohibitive for such applications.
The material cost of titanium alloys is generally high at least in part because the content of minor elements such as iron and oxygen need to be tightly controlled in the melt stock. Elements such as iron and oxygen may segregate when the melt solidifies, leading to non-uniform mechanical properties. To eliminate this effect, extra-low interstitial (ELI) grade alloys have been developed. For example, the aerospace material specification on ELI grade Ti-6Al-4V limits iron to 0.25 and oxygen to 0.13, in weight percent.
The processing cost of titanium is generally high at least in part because titanium alloys are typically wrought. Forming the titanium alloys to near-net shape by the working process can involve costly machining. Moreover, the working and machining can generate significant material waste.